Not Applicable
The fabrication of microelectronic components from a wotkpiece, such as a semiconductor wafer substrate, polymer substrate, etc., involves a substantial number of processes. Generally stated, there are four categories of processing operations performed on the workpiece to fabricate the microelectronic component(s). Such operations include material deposition, patterning, doping and heat treatment.
Material deposition processing involves depositing thin layers of electronic material to the surface of the workpiece (hereinafter described as, but not limited to, a semiconductor wafer). Patterning provides removal of selected portions of these added layers. Doping of the semiconductor wafer is the process of adding impurities known as xe2x80x9cdopantsxe2x80x9d to the selected portions of the wafer to alter the electrical characteristics of the substrate material. Heat treatment of the semiconductor wafer involves heating and/or cooling the wafer to achieve specific process results.
Numerous processing devices, known as processing xe2x80x9ctoolsxe2x80x9d, have been developed to implement the foregoing processing operations. These tools take on different configurations depending on the type of workpiece used in the fabrication process and the process or processes executed by the tool. One tool configuration, known as the Equinox(R) wet processing tool and available from Semitool, Inc., of Kalispell, Mont., includes one or more semiconductor workpiece processing stations that utilize a semiconductor workpiece holder and a process bowl or container for implementing wet processing operations. Such wet processing operations include electroplating, etching, etc.
In accordance with one configuration of the foregoing Equinox(R) tool, the workpiece holder and the process bowl are disposed proximate one another and function to bring the semiconductor wafer held by the workpiece holder into contact with a processing fluid disposed in the process bowl. Restricting the processing fluid to the appropriate portions of the semiconductor wafer, however, is often problematic.
Conventional semiconductor workpiece processors have utilized various techniques to facilitate complete exposure of these appropriate portions to the processing fluid while concurrently shielding the remaining portions of the semiconductor wafer that are not to be contacted. For example, such conventional systems may require application of tape to the back side of the semiconductor wafer to prevent process fluid from contacting the portions of the wafer beneath the tape. Other configurations use a suction cup arrangement for contacting and holding to the back side of the semiconductor wafer to thereby prevent the processing fluid from contacting the back side.
Although such conventional techniques often adequately fulfill the purpose of preventing process fluid from coming in contact with the back surface of the semiconductor wafer, such techniques present their own set of problems. For example, additional processing steps are required to apply the tape. Further, additional parts are required when a physical cover is used to prevent processing fluid contact with the back side of the workpiece. Still further, semiconductor workpieces are fragile and care must be taken not to damage the wafer during covering of the wafer surface. The increased wafer handling inherent in the conventional techniques increases the risk of wafer damage.
Therefore, the present inventors have recognized a need to improve on the techniques currently used to control the contact between the processing fluid and the appropriate portions of the semiconductor workpiece.